Steam heating system



0d. 7, 1 c. 1. HALL 2,258,245

STEAM HEATING SYSTEM Filed Sept. 28, 1939 Inventor: Chester I. Hall,

. His Attorney.

Patented Oct. 7, 1941 STEAM HEATING SYSTEM Chester 1. Hall, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application September 28, 1939, Serial No. 296,953

6 Claims.

This invention relates to steam heating systerns and more particularly to an arrangement for controlling the effective heat radiating surface of a steam heating radiator arranged within an enclosure.

In heating apartments or rooms within buildings and the like, it is necessary to provide a heater of such capacity as will produce the desired temperature within the enclosure during th coldest weather condition experienced. As the heating capacity of the heater is much greaterthan that normally necessary to satisfy the heating demand during the greater part of the heating season, it is desirable in order to satisfactorily and efliciently heat the enclosure to arrange some means for controlling the heat supply in accordance with the immediate demand. In the case of buildings heated from a central steam. plant and having one or more radiators arranged in each room, the effective heat radiating surface of each radiator may be controlled by regulating the amount of air within the radiator. Thus, upon a demand for heat by the room, a certain amount of air may be vented from the radiator, thereby increasing the effective heat radiating surface of th radiator and conversely, upon the room temperature rising above a predetermined value, air may be introduced into the radiator to diminish the effective heat radiating surface thereof. By such control a close modulation of the heating is effected in that a definite balance may b maintained. between the rate of heat supply to the enclosure and the rate of heat loss therefrom.

It is an object of this invention to provide a new and improved arrangement for regulating the effective heat radiating surface of a steam radiator whichis simple in construction, compact in design, and eflicient inoperation.

More specifically, it is anobject of this invention to provide a new and improved arrangement for regulating the amount of air within a steam radiator to control the effective heat radiating surface thereof in accordance with the conditions of temperature of the enclosure being heated.

In accordance with the illustrated embodiments of my invention, I provide a relatively small motor driven air pump which may be mounted upon or adjacent to the radiator, the pump being preferably connected for supplying air into the radiator at a point remote from the steam inlet thereto. A vent passage is provided in the connection between the pump and the radiator which is controlled by means responsive mostatically controlled vent passage is also arranged between the source of steam and the radiator to prevent air from being forced from the radiator into the remainder of the steam sys- For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto taken in connection with the accompanying drawing in whichFig. 1 is a sketch illustrating in a diagrammatic form one embodiment of my invention and Fig. 2 is a sketch illustrating a second embodiment thereof.

Referring to Fig. 1 of the drawing, a steam radiator I 6 is shown which is adapted to be connected by conduit II to a source of substantially constant pressure steam such as the central steam plant (not shown). The supply of steam from the inlet II to the radiator may be controlled by the manually operated valve l2, it being understood, however, that this valve is normally in the fully opened position during the operation of my heating control arrangement. Valve I2 is connected to the steam inlet of the radiator by a pipe l3. In this instance a onepipe heating system is illustrated in which condensate is adapted to be returned to the central plant through the steam supply pipe II.

In accordance with one embodiment of my invention I provide a relatively small air pump l5, preferably of th positive displacement type, which may be driven by a relatively small electric motor I6. As indicated in the drawing, the end of the motor shaft may be provided with a cam I l which is adapted to engage with the end of the spring biased pump piston rod l8 and operate it with a reciprocating motion. Th pump is provided with suitable non-return inlet and. discharge port valves (not shown) and is connected by means. of the pipe 19 and the thermostat valve 20 to the radiator. Provision is made for venting air from the radiator through the thermostat valve 20, pipe 2|, and the solenoid operated valve indicated generally at 22. The valve 22 may compris a non-magnetic casing 23 having a magnetic valve head 24 slidably arranged therein which is adapted to be operated to an upper or valve opening position by means of the solenoid coil 25. The movable valve head 24 is normally biased downwardly or to the seating position as by a spring 26 arranged between the upper end of the valve head 24 and the upper end of the casing 23 to close th vent opening 21 in the lower part of the casing 23.

to the temperature within the enclosure. Ather The valve head 24 may be provided with suitable longitudinal flutes 28 in its outer surface so that air may flow freely therepast toward the opening 2'! when the valve is in the opened position. An adjustable needle valve 29 is provided for regulating the size of the opening 21 for adjusting the rate of air flow from the radiator. The thermostat valve may be of any suitable type which will open to pass air there= through in either direction but will close when all air has been expelled from the radiator to prevent leakage of steam therefrom.

The air pump motor and the vent valve 22 are adapted to be alternatively operated in accordance with the temperature conditions of the enclosure to be heated. As illustrated in the drawing, a thermostat comprising a bi-metallic element 30 and a pair of oppositely disposed fixed contacts 3! and 32 is arranged adjacent the end of the radiator remote from the steam inlet thereto and may be mounted upon the motor support or directly upon the motor as'indieated. The element 30 is connected to one line 313 of a suitable source of supply. One contact 3| is connected in series with the motor 16 to the other supply line 34 while the other fixed contact 32 is connected in serieswith the solenoid coil to the supply line 34. In the operation of the system, consider first that the temperature of the enclosure drops below a predetermined value and that the heating capacity of the "radiator is to be increased. Under this condition, the thermostat element win bend to the right engaging with th'e'fixed contact 32, thereby com pleting an energizing circuit for the valve operating solenoid 25. As the valve head 24 is raised from its seat, air will be allowed to pass slowly from the radiator It through the thermostat valve 20 and vent opening 21 to atmosphere. It is understood that the opening 21' is so adjusted by means of the needle valve 25 so that a considerable period of time, such as, for example, twenty minutes, will be required for the radiator, if initially filled with air, to completely vent it self under normal steam pressure. This is desirable so that "the room temperature will 'increase substantially simultaneously with the increase of effective heat radiating surface of the radiator. By the arrangement of the "thermostat adjacent the end of the radiator asindicated, the effective heat radiating surface thereof will be increased by steps, the radiator itself functioning as a preheater for the thermostat element to prevent overshooting. With the air vent valve open the heating surface of the radiator will be relatively rapidly increased and momentarily the temperature of the air immediately surrounding the radiator will be increased to such a value that the thermostat element will disengage with the fixed contact 32, thereby 'effecti-n'g the closure "of the air Vent valve 22. Convection currents will soon carry radiated heat upwardly and acrossthe room so that after a relatively short "period of time the temperature of the air surrounding the thermostat 30 will be substantially equal to the temperature of the air elsewhere in the room. Should the room temperature still be low, the thermostat element 30 will again engage with the fixed contact 32 to continue the venting of air from the radiator and effecting a further increase in thQGfiCtlVB heat radiating surface of the radiator. The stepby step operation of the vent valve 22 will continue until the thermostat element 30 becomes stabilized in a non-contact ma-king position. In the eventthat the heat l'o'ss'from the room isso great that maximum heating surface of the radiator is required, all of the air will be vented therefrom and as soon as steam reaches the thermostat valve 20, it will close to prevent leakage of steam into the room through the vent valve 22.

Now assume that the enclosure temperature rises above a predetermined value during which condition the thermostat element 30 will bend to the left to engage with the fixed contact 3|, thereby energizing the pump motor l6. Air will thereupon be pumped through the thermostat valve "20 and into the radiator to force steam therefrom and diminish the effective heating surface thereof. The capacity of the pump 15 is relatively small so that a considerable period of time, such as, for example, twenty minutes, will be required for it to completely fill the radiator' with air in order that the room temperature may follow relatively closely with the decrease in the effective heating surface of the radiator. Depending upon such factors as the size of the room, the radiator, the period required for exhausting the radiator of steam may be varied as desired by selection of a proper size pump. As soon as the room temperature has dropped to the desired value, the thermostat element 3%) will disengage with the fixed contact (if, thereby deenergizing the pump motor [6; In the event that the pump motor is energized for a period of time greater than that required to completely discharge the steam from the radiator, the air passing into the steam connection I3 will cool the th'ermostat element within the valve 40, thereby opening the vent passage thereof to allow the excess quantity of air to escape therefrom. By the provision of the therm'ostat vent valve -40, as shown, the possibility of air being forced from the radiator into the remainder of the steam heating system is pro-3 cluded.

surface of the radiator will be adjusted to supply heat to the room at a rate substantially ba'lrinsed with the rate of heat loss. Variations in the rate of heat loss from the room will be ac companied by corresponding variations in the rate of heat supplied to the room,

in Fig. 2 is illustrated a second modification of the invention and in this instance is applied to a radiator of a two-pipe system, although it is obvious that it may be applied equally well to a radiator of a single pipe system in a manner similar to the arrangement in the first modification. lhe radiator 51' is adapted to receive steam through the supply conduit 52, the man; ual control valve 53 and connection 58. Condensate is drained from the radiator through the outlet pnnection 55, the float Valve indicated generally at '56, and drain conduit 57. 'Ifhe float valve, the purpose of which will be later described, maybe of any suitable type and-as illustrated, comprises a housing F8 having arranged therein a suitablefloat 59 carried upon the free end of a lever pivoted to the housing as at 61. Connected for operation by the float lever is a valve 62 which "is adapted to be movedto the opened position by the float 59 upon the level of condensate within the housing =58 rising above a predetermined point to allow passage of condensate into the drain "conduit "51. 1'

The heating control; apparatus of this modification comprises a suitable electric motor 65 fication. "I'hemotor B is adapted to be continuously energized from a suitable source of supplythrough connection 61 The air pump 66 is connected by conduit tfl withthe outlet end of the radiator 5| as, for example, through the upper portion ofthe housing 68 of the float valve 56 so thatthere is a continuously open passage interconnecting the pump and the radiator. Venting of air from the radiator is effected through athermostatically controlled valve 69 suitably connected to the conduit E8 and forming a venting passage having a vent opening I l. The escape of air through the vent opening is controlled by a suitable thermostatelementi which may be mounted adjacent the radiator at the end thereof remote from the, steam inlet as, for example, upon the motor supporting bracket 13. As in the modification previously described, a thermostat valve is provided in the inlet connection 54 for precluding the passage of air from the radiator 5| intov the remainder of the steam system.

In the operation of the apparatus of this modification, assume first that the enclosure temperature drops and that the effective heat radiating surface of the radiator 5| is to be increased. Upon this condition occuring, the thermostat element 12 will bend to the left farther away from the vent opening H so that air will be allowed to escape at a rate higher than the output of the pump thereby decreasing the volume of air confined within the radiator. It is to be understood that the vent opening H is of such a size that air may flow therefrom at a rate greater than the output of the pump 66 and so that a considerable period of time, such as, for example, minutes, will be required for completely venting the radiator should it be initially filled with air. As steam enters the radiator 5|, replacing the air discharged therefrom and increasing the effective heat radiating surface thereof, the increase in radiated heat will act upon the thermostat element 12 as a preheater to cause it to somewhat restrict the vent opening. Convection room currents will circulate the increase in radiated heat from the radiator and the thermostat element 12, which is arranged adjacent the cool end of the radiator, will again move to a farther port opening position. More air will then be vented from the radiator until the thermostat element 12 arrives at a balanced position wherein air is vented at a rate proper for the maintenance of the effective heating surface in substantial accordance with the rate of heat loss from the room.

Conversely, upon a condition of rising room temperature the thermostat element 12 bends toward the right to restrict the vent opening H and reduce the rate of air flow from the vent opening thereby causing the pump to force air into the radiator and increase the volume of air confined therein. The effective heat radiating surface of the radiator will be correspondingly decreased by the increase in the amount of air therein until eventually, in the extreme case, all of the steam will be forced therefrom back into the conduit 52. Passage of air into the steam supply conduit 52 and the remainder of the heating system is precluded by the provision of the thermostat vent valve 75 which will open as soon as the air strikes it to vent the surplus air to atmosphere. By the arrangement of the float valve 56 between the condensate discharge outlet of the radiator and the drain conduit 51, passage of air from the pump 66 into the drain conduit 51 is precluded. 1 l l 1 J In thisarrangement, the position of the thermostat=blade will'vary with respect to the vent aperture to vary the rate of air flow therefrom smoothly and continuously corresponding to deviations in room temperature from apredetermined value. Even modulated control is effected without overshooting'in a simple and efficient manner, e I a 'While I have shown and described myinvention asbeing applied to an individual room radiator, it is obvious that the apparatus may be adapted for controlling the heating of an en closure through a central heating plant. In such an; embodiment the steam radiator arranged within the circulating air duct is represented by either of the radiators shown in the drawing, while the arrangement of the heating control appar'atus will be substantially the same as that shown and described.

Having described the principle of operation of my invention togetherwith the apparatus which I now consider to represent the best embodiments thereof, I desire to have it understood that the apparatus shown is merely illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a heating control system for a radiator connected to a steam source and arranged to supply heat to an enclosure to be heated, a source of air under pressure greater than said steam source, a conduit forming a continuously open passage interconnecting said air source and said radiator, means for venting air from said conduit at a variable rate, the flow of air into or out of said radiator being determined by the rate of air flow through said venting means, and means influenced by the temperature of said enclosure for varying said venting rate.

2. In a heating control system for a radiator connected to a source of steam and arranged to supply heat to an enclosure to be heated, a source of air under pressure greater than the pressure of said steam source, a conduit forming a continuously open passage interconnecting said radiator and said source of air, an air vent connected to said radiator having a restrictable opening so arranged thatwhen said opening is restricted less than a predetermined amount the volume of air confined in said radiator increases and when said opening is restricted greater than said predetermined amount the volume of air confined in said radiator decreases, and means for varying the restriction of said vent opening above and below said predetermined amount in accordance with the deviations of the temperature of said enclosure from a predetermined value.

3. In a heating control system for a radiator connected to a steam source and arranged to supply heat to an enclosure, a source of air under pressure greater than said steam source, a conduit forming a continuously open passag interconnecting said air source and said radiator, a venting passage connected to said conduit, said venting passage having an opening, means for restricting said opening, said opening being of such size that the flow of air into and out of said radiator is determined by the amount said opening is restricted, means influenced by the temperature of said enclosure for varying the restriction of said opening, and means for preeludin a, from of steam from said radiator through; said ventingpassage.

4. In a heating control system for a, radiato connected to a. steam source; nd arran ed to sunp w heat, t an, e clo u e, tube. h a edia source or air under p essure reater than sa d. steam sourcc-,. a onduit formm; a ontinuously pen passa e interconne t n 3 64 11 source and said ra iatcr, an ventina pa s e nn cted o.v said.- -9. flint said venting p s v n n QPQnin means for restricting said opening, said opening bein i s ch s ze hat the flow of ir nt and out cf; said radiatoris determined by the, amount said. w -i ;v s; t c d, ndm ans: for a -y in the restriction of said opening inaccordance the temperature'of said enclosure.

5,111, a heating; control; system having a radi-. atop connected to; a source of steam'and; arranged to supply heat. to an enclosure, a. source or air havin a pressure greater n sa d S e m s lrce conduit means forming a continuously open passage interconnecting said air source, and aid radiator, a venting passage connected torsaid conduit means, said venting passage having an opening through which air is vented from said conduit, said opening being ofsuch a size that when it is unrestricted air flows out, of said raditQ-I: thr u h said e in ut sa d, on e: insis' restricted ir lows rom said.- s f e sai ra ia or through id condu t m ans nd a bim t llic. membe l c ed in said e losu e and movable accordance with the tempera: tit e, v riat ons. h reof, d bimetallic mber having a portion movable adjacent said opening to; restrict the flow ct air therethrough and thereby ccntr l he. o o a n nd: out f said; radi tor n s d n i the mp ra ntent a d enclcsur 6. Apparatus for controlling the effective heating; surface of a radiator connected to a source of steam coniprising, a source of air under pres} sure g eater than said steam source, aconduit i'qrrni a continuously open passage intercom necting said source of air and said radiator, a Venting passage communicating with said cond it, said ventingp ee having an openin means for restricting said opening said open-E i-ng being of such siz that the flow of air into and out of said radiator'is determined by the amount. said opening is. restricted, and means for varying the restriction of said opening to control the flow of air into and ou of said radiator.

CHESTER I. H LL. 

